GE D90 Plus Instruction Manual page 337

CHAPTER 7: PROTECTION
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
The operand is asserted by the autorecloser 1.5 cycles after single-pole
AR FORCE 3-P TRIP
reclosing is initiated. This operand calls for a three-pole trip if any protection element
configured under which this setting remains picked-up. The open pole detector provides
blocking inputs to distance elements; as such, the distance elements immediately reset
after the operand is asserted. For other protection elements used in single-
TRIP 1-POLE
pole tripping, the user must ensure that they reset immediately after tripping; otherwise
they are detected as an evolving fault if they remained picked up and the relay then
executes a three-pole trip.
For example, if a high-set phase instantaneous overcurrent is used (
set to "PHASE IOC1 OP"), then the
of the instantaneous overcurrent element. In this case, after tripping phase A, the phase
A instantaneous overcurrent element is forced to reset. Phases B and C remain
operational and can detect an evolving fault as soon as 8 ms after tripping phase A. The
neutral and negative-sequence instantaneous overcurrent elements shall be blocked
from the
OPEN POLE BLK N
prevent pickup during single-pole reclosing.
Trip Reclose Input 1, Trip Reclose Input 2, Trip Reclose Input 3, Trip Reclose Input 4, Trip
Reclose Input 5, Trip Reclose Input 6
Range: any FlexLogic operand or shared operand
Default: OFF
These settings select an operand representing a fault condition that initiates three pole
reclosing (for example, phase distance zone 1). Use an OR-gate if more than six inputs
are required.
Trip Force 3-Pole
Range: any FlexLogic operand or shared operand
Default: OFF
This setting selects an operand that forces an input selected for single-pole operation to
produce a three-pole operation. The
value for this setting. Power system configurations or conditions that require such
operations can also be considered.
Trip Pilot Priority
Range: 0 to 65.535 seconds in steps of 0.001
Default: 0.000 seconds
This setting specifies an interval equal to the inter-relay channel communications time,
plus an appropriate margin, during which outputs are not asserted. This delay permits
fault identification information from a remote terminal to be used instead of local data
only.
Reverse Fault
Range: any FlexLogic operand or shared operand
Default: OFF
Use this setting to guarantee accuracy of single-pole tripping under evolving external-
to-internal faults. When a close-in external fault occurs, the relay is biased toward very
fast operation on a following internal fault. This is primarily due to depressed voltages
and elevated currents in response to the first, external fault. The phase selector can
exhibit some time lag compared to the main protection elements. This can potentially
result in a spurious three-pole operation on a single-line-to-ground internal fault.
Delaying tripping on internal faults that follow detection of reverse faults solves the
problem.
As long as the operand selected with this setting remains asserted, the trip action is
delayed by the time specified by the
operand is to combine reverse zone indications (such as zone 4 pickup) with a half-cycle
operand is used for blocking phase A
OPEN POLE OP ?A
operand unless the pickup setting is sufficiently large to
FlexLogic operand is the recommended
AR DISABLED
Trip Delay on Evolving Faults
CONTROL ELEMENTS
is
Trip 1-Pole Input 1
setting. Typically, this
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